23andMe Research Findings

For many people fresh cilantro is a beloved ingredient in their favorite dishes. Others find the herb practically inedible, likening the taste to soap, mold, and dirt. The story behind this love-hate reaction is partly genetic.

The proportion of people who dislike fresh cilantro (also known as coriander) varies by ethnicity and genetic factors are suspected to play a role. In the largest genome-wide association study of cilantro preference to date, 23andMe scientists compared genetic data from more than 25,000 individuals with European ancestry who declared whether they liked the taste of fresh cilantro or whether they thought cilantro had a soapy taste. We found that people with the AA genotype at rs7107418 had higher odds of perceiving a soapy taste in cilantro and higher odds of disliking the herb compared to those with the AG genotype, and people with the GG genotype had lower odds of perceiving a soapy taste or disliking cilantro. This SNP is close to a number of genes coding for olfactory receptors, one of which (OR6A2) is involved in detecting certain chemical compounds called aldehydes that are key components of cilantro aroma.

The SNP highlighted in this study is rs72921001, which is not directly tested by 23andMe but was inferred from nearby SNPs. We provide information for rs7107418 above, which is highly correlated with rs72921001 in individuals of European descent.

SEPTEMBER 2012

Cilantro as a matter of taste

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People with Parkinson’s disease suffer from a number of motor symptoms but it appears that they may have better than average metabolic health.

Parkinson’s disease is a degenerative disorder that attacks the central nervous system, but there are some health conditions for which people with Parkinson’s tend to have more positive outcomes. When 23andMe researchers looked at associations between Parkinson’s disease and more than 1,000 other traits, conditions and diseases, they found that people with the condition tend to have lower cholesterol and body mass index, and lower rates of type 2 diabetes.

23andMe Research customer survey data

At first blush, these traits seem to have no obvious connection to Parkinson’s disease. The associations may indicate a true relationship between, say, cholesterol metabolism and the development of Parkinson’s, or they may simply reflect some other underlying phenomenon. At the very least, they open up interesting directions for further research.

APRIL 2012

Parkinson’s, Cholesterol, Type 2 Diabetes and BMI

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Researchers at 23andMe have found that along with impacting a person’s motor skills Parkinson’s disease is also associated with back pain and the need for joint replacement surgery for some patients.

Parkinson’s disease is a degenerative disorder of the central nervous system characterized by symptoms including tremors and difficulty in walking. Our researchers looked at associations between Parkinson’s and more than 1,000 different traits, conditions or diseases. We found a number of seemingly unrelated phenotypes that are associated with the condition, including associations with back pain and joint replacement surgery, both of which occur more frequently in people with Parkinson’s disease.

23andMe Research customer survey data

The symptoms of diseases often offer obvious clues for researchers to search for causes and potential treatments, but seemingly unrelated symptoms may also offer important clues in places where no one would have thought to look. These unexpected twists may help unravel the molecular pathways for a disease, or even lead to promising new treatments.

APRIL 2012

Parkinson’s Disease, Back Pain and Joint Replacement

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Researchers at 23andMe have found that people with Parkinson’s disease tend to have certain personality traits and preferences.

Parkinson’s disease is a degenerative neurological illness that results in a progressive loss of motor skills. In addition to exploring the genetic basis for the disease, 23andMe researchers have also discovered some interesting characteristics about people suffering from this condition. The disease is associated with certain personality traits including being more agreeable, more neurotic and anxious, and being less extraverted. The researchers also found that those with Parkinson’s were less likely to have sky-dived or had liposuction, but more likely to prefer sweet foods over salty ones.

23andMe Research customer survey data

Because Parkinson’s disease involves the loss of neurons in certain parts of the brain, it may help explain certain personality tendencies. Then again, some of the associations may be a reaction to the symptoms of the disease itself. It has also been reported that some Parkinson’s patients develop a “sweet tooth.” Whether some of these correlations lead to significant insights or treatments remains an open question.

APRIL 2012

Parkinson’s Disease and Personality

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We replicate an association between inherited variation in the JAK2 gene and rare blood cancers linked to another JAK2 mutation that can appear later in life.

Myeloproliferative neoplasms (MPN) are a group of rare blood cancers that includes myelofibrosis (MF), essential thrombocythemia (ET), and polycythemia vera (PV). These disorders are mysterious but we do know something about the genetics. There is a particular mutation (V617F) in a gene called JAK2 that nearly all people with the PV form of MPN have, and that many people with MF and ET have. People aren’t born with the V617F mutation, but some “acquire” it later in life in their blood cells.

The rap sheet for JAK2 doesn’t stop there. In 2009 several studies in individuals with European ancestry found an inherited variant in JAK2 associated with MPN and the V617F mutation. A more recent study in Japanese MPN patients identified a very similar association. By looking at 23andMe’s growing MPN cohort (all of European descent), we found additional evidence linking inherited variation in JAK2 to MPN. In our database, people with the G version of rs12340895 in the JAK2 gene have 2.2 times higher odds of V617F-positive MPN. (Read more about MPN and the role of JAK2 in our blog post.)

In August of 2011, 23andMe launched a research initiative to study MPNs with a goal of reaching 1,000 participants. We’re nearly at 500 participants just six months later and are already making exciting discoveries. Although still preliminary, our finding supports previously published research. More importantly, we’ve demonstrated that our unique research platform can very quickly make an impact in the study of rare diseases.

We’ve plucked out four interesting genetic variants associated with why some people have a unibrow.

Salma Hayek, the late Soviet leader Leonard Brezhnev and Sesame Street’s Bert are not a troika that immediately pops to mind. But they do have one fuzzy line linking them and that’s their unibrows. Scientist at 23andMe found several distinct genetic variants that contribute to why some people’s eyebrows are joined in the middle and some are not. In people with European ancestry, the less common versions of rs12913832 (A), rs2894450 (G), rs7702331 (G), rs16940676 (A), rs35390 (C), rs2804344 (C), rs10135580 (T) and rs4629598 (G) are all associated with having more of a unibrow. In addition, the less common versions of three other variants are associated with having less of a unibrow — rs1337630 (A), rs1178118 (C) and rs11749542 (A).
Interestingly, several variants associated with unibrow are also associated with other morphological traits. For example, the A version of rs12913832 is associated with both brown hair and a thicker unibrow.

23andMe Research customer survey data

What this and other associations uncovered by 23andMe scientists show is that traits are not controlled by just one variant, but often a large number of different variants on different genes. Sometimes these specific variants affect other traits as well, and sometimes the same genes and pathways are involved with the development of different traits.

JANUARY 2012

The highbrow and lowbrow of unibrow

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We know your genetics can tell you about where you or your ancestors are from, but that ancestry is also associated with certain physical traits such as the color of your eyes, or how likely your hair will be blond or brown or the darkness of your skin.

By comparing the ancestry inferred by the genetics of customers of European ancestry with their survey responses, 23andMe scientists identified a number of physical traits associated with a person’s predicted ancestral origin in Europe. In some cases what researchers found is very intuitive — people with Northern European ancestry are more likely to have blue eyes and blond hair, while the hair and eyes of people with Southern European ancestry are more likely brown. Of course not all Northern Europeans have blond hair and blue eyes and not all Southern Europeans have dark hair and brown eyes. So, while genetic ancestry does account for a lot of variation in hair and eye color, other factors are likely involved as well.

PCA plot of genetic ancestry and eye color (click to enlarge)

23andMe Research customer ancestry data

PCA plot of genetic ancestry and eye color

Customer data for blue and brown eyes are plotted on a two-dimensional graph and distributed based on genetic ancestry. The likelihood of having blue vs. brown eyes correlates strongly with genetic ancestry within Europe. To see more about what DNA can say about ancestry, traits and disease risk go here.

OCTOBER 2011

Don't it make your brown eyes blue

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23andMe researchers can use a person's ancestral origin to show associations with social and cultural traits like whether you drink too much or whether you are an extravert.

23andMe researchers found that a number of social and cultural traits were strongly associated with a person’s predicted genetic ancestry of origin in Europe. Self-reported diagnoses of alcoholism were more common than average among people of predicted Irish ancestry, while people with predicted Balkan ancestry were more likely to describe themselves as extraverts.

These associations and others that we found beg many questions. First do they reflect actual traits among people of different European ancestry or are they simply a reflection of cultural stereotypes among 23andMe customers? More intriguing is the question of whether these traits are influenced by genetics. While the statistical correlations in the data are strong, we still don’t have a complete picture of why these traits appear to separate according to ancestry.

PCA plot of genetic ancestry with alcoholism and extraversion (click to enlarge)

23andMe customer data

PCA plot of genetic ancestry with alcoholism and extraversion

Customer data for alcoholism and extraversion are plotted on two-dimensional graphs and distributed based on genetic ancestry. The likelihood of having been diagnosed with alcoholism and the degree of extraversion for individuals are correlated with genetic ancestry within Europe. To see more about what DNA can say about ancestry, traits and disease risk go here.

OCTOBER 2011

Genes, geography, and socio-cultural traits

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23andMe researchers can use a person’s ancestral origin to show associations with certain diseases like Parkinson’s and the most common type of skin cancer.

Using data from thousands of 23andMe customers of European descent, our researchers found that ancestry may be important in determining the risks for Parkinson’s disease and for basal cell carcinoma, the most common type of skin cancer.

Among 23andMe customers with European ancestry our researchers found that the diseases were more often reported among those with ancestry from western and northwestern countries in Europe.

Customer data for Parkinson's disease and basal cell carcinoma (the most common form of skin cancer) are plotted on two-dimensional graphs and distributed based on genetic ancestry. The likelihoods of having been diagnosed with these two diseases are correlated with genetic ancestry within Europe. To see more about what DNA can say about ancestry, traits and disease risk go here.

While the causes of these disease associations with ancestry are still unclear — to what extent are the effects due to genetics versus geographic variation in environmental factors? — the fact remains that ancestry is an important factor in understanding disease risk. While many risk models (including 23andMe’s current model) treat all Europeans collectively as having the same baseline level of risk, factoring in a person’s specific ancestral origins may be important part of any predictive model meant to assess a person’s risk for disease.

OCTOBER 2011

Ancestry and disease risk

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It’s no secret that the majority of African Americans have European ancestry, but what’s less well known is how many Americans who consider themselves white or of European ancestry have African ancestry.

23andMe researchers looked at the genetic ancestry of about 78,000 of its customers who would identify as entirely of European descent and found that from 3 percent to 4 percent of them have "hidden" African ancestry. The percent of African ancestry is relatively low — less than 5 percent with the majority of individuals having just .75 percent and 1.5 percent — which suggests that those people have an African ancestor who lived about seven generations ago, or about 200 years ago.

Distribution of percent of African ancestry among our users. (click on image to enlarge)

23andMe customer ancestry data

Distribution of percent of African ancestry among our users.

Distribution of percent of African ancestry among our users who have 5 percent or less African ancestry based on genetics. About 3-4 percent of people who are likely to consider themselves as entirely of European ancestry have "hidden" African ancestry. The majority of these individuals have just 0.5 percent to .75 percent — which suggests that those people have an African ancestor who lived about six generations, or about 200 years, ago.

While much lower than the average proportion of European ancestry that African Americans have — which is from 20 percent to 25 percent — the small percentage of African ancestry that some European Americans have suggests a new narrative for the social history of American race relations.

The tradition of the "Rule of Hypodescent" — or more commonly known as the "one drop rule" — was that anyone with any African ancestry was considered black. But 23andMe’s finding suggests that during the era of slavery at least some "mixed race" people were integrated back into the European American community. See more on the finding here.

SEPTEMBER 2011

Not so black and white

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Your genetics not only indicates whether or not you are of European descent, but it can also predict from where in Europe you or your ancestors came.

People of European descent share a lot in common. But just as spaetzle and spaghetti share some commonalities, they are also very different, kind of like Germans and Italians. That difference, and the difference among all Europeans — or among people of different European ancestry — can be seen in the DNA. Even in the relatively tight geography of Europe, people have developed enough genetic variation that 23andMe researchers can predict their country of origin.

Using principal component analysis (PCA) and linear regression — statistical tools for processing and visualizing large, complex datasets — researchers at 23andMe analyzed genetic data from 3,000 customers who all had four grandparents from the same country of origin. When the results of the analysis are plotted on a two dimensional graph, individuals of similar ancestry cluster together, and those clusters correspond closely to the geographic locations of the countries of Europe. (See map below.)

PCA plot of genetics closely reflects ancestry

23andMe customer ancestry data

PCA plot of genetics closely reflects ancestry

Individual customers are plotted on a two-dimensional graph based on their genetic data and labeled based on their self-reported ancestry information. Individuals of similar ancestry tend to cluster together, and the clusters correspond closely to the actual geography of Europe. To see more about what DNA can say about ancestry, traits and disease risk go here.

This is more than just a parlor trick for data scientists. These maps illustrate that Europeans and people of European ancestry are not homogeneous groups. In fact they are genetically diverse. Those differences also manifest themselves in other ways — from variation in physical traits, to disease susceptibility and even socio-cultural characteristics.

Hair color is determined by the amount of two different kinds of pigments—eumelanin for brown and black hair or pheomelanin in red hair. A person with low levels of both of those pigments will have blonder hair. The genetics of hair color isn’t fully known but many genes factor into the equation.

23andMe scientists have discovered that a person of European descent with the C version of rs9544611 near the EDNRB gene is more likely to have blonder hair. We also replicated a previously published association between the C version of rs1667394 and substantially lower odds of blond versus brown hair.

23andMe Research customer survey data

This discovery doesn’t tell us whether blondes have more fun, but may help us understand the function of genes and how they express themselves. The gene EDNRB doesn’t just play a role in pigmentation: researchers have found that a variant within the gene is associated with Hirschsprung disease, a serious bowel disorder. In horses, a different variant in the middle of the EDNRB gene causes Lethal White Syndrome. Foals with the disease are all, or nearly all white and die shortly after birth due to intestinal blockage.

SEPTEMBER 2011

Blonde on blonder

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23andMe scientists have started unraveling the genetics of why some people’s stomachs turn when the car does.

Some people find road trips and lake outings relaxing. Those who suffer from motion sickness, however, often turn green—not just with envy, but from nausea. By analyzing our customers’ genetic data and responses to surveys, we’ve identified two genetic variants associated with motion sickness. In people of European descent, those with the G version of rs17720662 had slightly higher odds of having ever experienced motion sickness in a car, boat, or plane. Those with the A version at rs1347098 also had slightly higher odds of experiencing motion sickness.

23andMe Research customer survey data

SEPTEMBER 2011

Are we there yet? Clues to motion sickness

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Here at 23andMe we wax not so poetically about back hair. Our scientists have found several genetic associations for upper and lower back hair — and yes, there’s a difference!

23andMe researchers have found more than half a dozen common genetic variants associated with upper and lower back hair. At least four variants are associated with lower back hair or the lack of it, while there are two variants with strong associations with upper back hair. Among people of European ancestry the less common versions of rs13027881 (A), rs12755921 (A), rs485454 (G), and rs6525337 (C) are all associated with having less lower back hair. The less common version of rs1819910 (A) is associated with slightly more. As for upper back hair, the C version of rs8003865 is associated with slightly more hair, while the C version of rs2473896 is associated with slightly less.

23andMe Research customer survey data

This information isn’t just interesting for the unusually hirsute, but tells us something new about common physical traits. It turns out that traits like back hair are not controlled by just one variant, but often a large number of different variants on different genes. And the fact that the genetic variants associated with upper back hair are quite distinct from those associated with lower back hair suggests that different biological pathways govern these seemingly similar traits.

SEPTEMBER 2011

The backstory on hair

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We found several genetic variants associated with attached and unattached earlobes.

Whether your earlobes dangle with your earrings or are attached has a genetic association. Our researchers found six distinct genetic variants that contribute to this trait. Based on our customer survey data, people of European ancestry with the less common versions of rs7739444 (T), rs1035150 (T), rs2804344 (T), rs12691702 (G), and rs453609 (G) had lower odds of unattached earlobes. Those with the A version of rs11013962, on the other hand, had higher odds of unattached earlobes.

23andMe Research customer survey data

Why does something as seemingly insignificant as whether our earlobes are attached matter? Understanding the genetic association may help explain more than just appearance. Traits can also be indicative of other health risks—for instance, earlobe creases have been associated with heart attack and certain growth disorders.

SEPTEMBER 2011

Getting attached to earlobe genetics

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A study published in Nature Genetics in June 2011 identified three new genetic associations for migraines. We analyzed our customer data and replicated the same associations in just a few days.

Researchers at Brigham and Women’s Hospital in Boston recently identified three new genetic associations for migraines in individuals of European ancestry. By analyzing data we’d already collected from 23andMe customers, our scientists were able to replicate the same associations in a fraction of the time it usually takes other researchers to conduct such studies. In the Boston study as well as in our database, the C version of rs2651899 is associated with slightly higher odds of migraines, the C version of rs10166942 is associated with slightly lower odds of migraines, and the T version of rs11172113 is associated with slightly higher odds of migraines. Our analyses also supported a finding by the Boston researchers contradicting a study published last year, which reported a link between rs1835740 and migraines. Both the new study and our own analyses found no evidence for such an association.

23andMe customer survey data

While our results simply confirm a study done by other researchers, the process illustrates the power of 23andMe's database. In a fraction of the time, our scientists can make queries about suspected associations and confirm—or question—findings reported in other studies. (Read more in our blog post.)

23andMe scientists discovered two genetic variants associated with whether a person’s big toe or second toe is longer.

For most people the big toe, is the longest toe, but for some people the second, or "pointer" toe, is longer. Scientists at 23andMe have now identified two genetic variants associated with the relative sizes of the big toe and pointer toe. In our customers who have European ancestry, the A version of rs143383 and the T version of rs1479643 are both associated with slightly higher odds of having a longer big toe. One of these variants is in a gene called GDF5, which is believed to be involved in skeletal development.

23andMe Research customer survey data

AUGUST 2011

Eeny, meeny, miny, moe, what's your biggest toe?

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Scientists at 23andMe have found two new genetic associations with chin dimples.

Kirk Douglas passed his chin dimple to his son Michael, but what appears to be a straightforward inherited trait in the Douglas family has a lot more moving parts. How much of a chin dimple you have—very pronounced, slight, or none at all—has to do with common variants in many different genes. So far, researchers at 23andMe have identified two genetic variants associated with the trait in people of European ancestry. The C version of rs10953183 is associated with more pronounced chin dimple and the C version of rs7568419 is associated with less of a chin dimple.

23andMe Research customer survey data

AUGUST 2011

You've got something on your chin

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We’ve identified two new genetic associations and new evidence that genetics plays an important role in Parkinson’s disease.

With the help of our Parkinson’s Disease research community — the largest single, genotyped Parkinson’s cohort in the world — we have discovered two new genetic factors associated with the disease in people with European ancestry. One of these SNPs, rs11868035, requires further study to establish its effect. The other SNP, rs6812193, is located near a gene called SCARB2 that is already known to be involved in biological processes relevant to Parkinson’s disease; the T version is associated with slightly lower odds of the disease.

Our scientists were also able to confirm 20 other previously identified associations with Parkinson’s. Using additional analyses, they showed that late-onset Parkinson’s disease, long considered a mystery genetically, is influenced substantially by genetic factors. Many more genetic factors are yet to be discovered.

Our research data suggests two novel connections between genetics and hypothyroidism, a condition that affects about 5% of the population, especially women over the age of 50.

With the help of our research participants, we have identified several genetic variants that may be associated with risk for hypothyroidism in individuals with European ancestry. The SNPs
rs965513 in the FOXE1 gene and rs2476601 in the PTPN22 gene have already been reported in studies of thyroid function or thyroid disease. Two other associations are completely novel — the C
version of rs4915077 in the VAV3 gene is associated with slightly higher odds of hypothyroidism based on our research data, while the T version of rs3184504 in the SH2B3 gene appears to have
a slightly protective effect. Many of these genes are involved in the immune system.

The trait of "wet" or "dry" earwax was once thought to be determined by a single gene, but our research suggests another gene, PKD1L3, is adding to the stickiness of the picture. (Photo credit: Gregory F. Maxwell)

The association between variation in the ABCC11 gene and earwax consistency is well-established — people with at least one copy of a C at rs17822931 should have wet earwax, and people with
no copies should have dry earwax. But survey responses from our customers indicate that it's not so cut and dry. We discovered that having two copies of an "A" at rs9938025 is associated
with moderately lower odds of dry earwax and having two copies of a "G" is associated with moderately higher odds in our customers with European ancestry compared to those who have "AG".

23andMe customer survey data

JUNE 2011

Wet and dry earwax isn't all about one gene

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Many types of allergies group together in our customers — some unsurprising, but others that might make you, well, scratch your head.

If you're like 20% of Americans, you probably suffer from at least one allergy. It might not surprise you that people with allergies tend to be allergic to multiple things, but what
allergies tend to group together? Based on research survey data, we found that people are often allergic to more than one of cats, dogs, trees, weeds, grasses, mold, and dust mites. On the
other hand, most food allergies are not associated with most other types of allergies — and not even strongly associated with other food allergies in our participants. And the allergies that
are most likely to occur together? Stinging insects. Ouch!

Correlations between pairs of allergens that we asked about in our survey. (click on image to enlarge)

23andMe customer survey data

Correlations between pairs of allergens that we asked about in our survey

Allergens are listed identically down the side and across the bottom. The darker the square, the more likely it was that a person who said they were allergic to the substance on the right
also said they were allergic to the substance on the bottom

JUNE 2011

Allergies of a feather flock together -- sometimes

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We found a genetic association with why some people sneeze when they go from darkness to light.

A certain genetic variant increases the likelihood of having this photic sneeze reflex — also known as the ACHOO syndrome, and yes that's its technical name. We discovered that each copy of
the C version of rs10427255 is associated with 1.3 times increased odds of having the trait in people with European ancestry.

23andMe Research customer survey data

The reflex is harmless but understanding this common trait could help scientists better understand other light-triggered reactions, such as some types of epileptic seizures.

Our research identified a single nucleotide polymorphism (SNP) called rs4481887 associated with the likelihood of being able to smell asparagus in urine.

Our researchers discovered that in people with European ancestry, each copy of A at rs4481887 was associated with 1.7 times higher odds of smelling asparagus in urine compared to people with
two Gs at that SNP.

23andMe Research customer survey data

Strange and icky as it might be the discovery is significant for what it tells the genes that control our olfactory receptors — the proteins that detect chemicals in the air and transfer the
signals to the brain.
Understanding how and why some of us can detect smells is part of the larger scientific goal of learning how we evolved. In turn, this knowledge can help us understand the significance of
changes in the sense of smell, as are seen in people with various psychiatric conditions. This knowledge could be important for developing screening, prevention or treatment methods.

23andMe scientists identified two genetic variants associated with the amount of curliness in hair.

Hair's curliness — or the lack thereof — comes from the shape of the bulb at the base of the hair follicle. In people of all ethnicities, a curved bulb means your hair is going to be curly.
This trait has a genetic component. Each copy of the T version at rs7349332 was associated with slightly curlier hair. Each copy of the A version of rs17646946 was associated with slightly
straighter hair.

23andMe Research customer survey data

While this might not help you on a bad hair day, it could help scientists in other areas. Several serious diseases include hair abnormalities as a symptom, often in addition to other
malformations of the face and skin. Understanding how normal hairs develop may give scientists clues about these diseases and how they might best be treated.

There are a few genetic variants associated with freckling and scientists at 23andMe have identified one more.

23andMe researchers found an additional single nucleotide polymorphism (SNP) associated with freckling. We found that the C version of rs2153271 is associated with less freckling than the T
version of the SNP.

23andMe Research customer survey data

Freckles aren't a problem, but melanoma, a deadly form of skin cancer, is. Like freckles, melanoma is derived from melanin-containing cells. Understanding the genetics of freckling may help
researchers learn more about skin cancer and how to prevent or treat it.

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Our EU product is in English only, and due to applicable regulations it is only available for customers with a shipping address in Denmark, Finland, Ireland, Sweden and the Netherlands. If you are shipping to one of these countries continue to the: EU site →